This invention relates to water swellable absorbent aerated films or laminates made from crosslinked polyelectrolytes, and methods for their preparation.
It is known from U.S. Pat. Nos. 3,669,103 and 3,670,731 that crosslinked polymeric sorbents can be sandwiched between flexible supports to achieve disposable diapers or dressings.
The patent application by W. D. Burkholder, Ser. No. 565,880, filed Apr. 7, 1975, discloses methods of curing polyelectrolytes to make water swellable films wherein the curing or crosslinking agent is a polyamido-polyamine epichlorohydrin adduct. The patent to J. R. Gross, U.S. Pat. No. 3,980,663, discloses absorbent articles films, etc. and methods for their preparation wherein the crosslinking agents used are difunctional crosslinking agents which are reactive with carboxylate groups.
However, it has been found that the films prepared by Ser. No. 565,880 and U.S. Pat. No. 3,980,663 do not have the required rapid water absorbency rate so that water, urine, and other hydrophilic body fluids will be absorbed substantially within the time period required for practical use as in disposable diapers or pads.